Fix automatic session title generation

src/server/sessions/piSessionService.ts

@@ -15,7 +15,7 @@ import { BUILTIN_COMMANDS } from "./builtinCommands.js";
 import { SessionCommandService } from "./sessionCommandService.js";
 import { SessionArchiveStore } from "./sessionArchiveStore.js";
 import type { ActiveSession } from "./sessionRuntimeStore.js";
-import { generateShortSessionName } from "./sessionNameGenerator.js";
+import { fallbackSessionName, generateShortSessionName } from "./sessionNameGenerator.js";
 
 function noop(): void {
   // Intentionally empty default unsubscribe callback.
@@ -263,14 +263,18 @@ export class PiSessionService {
     if (model === undefined) return;
 
     void generateShortSessionName(this.modelRegistry, model, firstMessage).then((name) => {
-      if (name === undefined || session.sessionName !== undefined) return;
+      this.applyGeneratedSessionName(session, name ?? fallbackSessionName(firstMessage));
-      session.setSessionName(name);
-      this.publishSessionName(session);
     }).catch(() => {
-      // Session naming is best-effort and must not affect prompt handling.
+      this.applyGeneratedSessionName(session, fallbackSessionName(firstMessage));
     });
   }
 
+  private applyGeneratedSessionName(session: AgentSession, name: string | undefined): void {
+    if (name === undefined || session.sessionName !== undefined) return;
+    session.setSessionName(name);
+    this.publishSessionName(session);
+  }
+
   private publishSessionName(session: AgentSession): void {
     const event = session.sessionName === undefined
       ? { type: "session.name", sessionId: session.sessionId } as const

src/server/sessions/sessionNameGenerator.test.ts

@@ -0,0 +1,18 @@
+import { describe, expect, it } from "vitest";
+import { cleanSessionName, fallbackSessionName } from "./sessionNameGenerator.js";
+
+describe("sessionNameGenerator", () => {
+  it("cleans model-generated titles", () => {
+    expect(cleanSessionName('Title: "Fix Session Naming."\nextra')).toBe("Fix Session Naming");
+  });
+
+  it("builds a concise fallback from the first request", () => {
+    expect(fallbackSessionName("Seems like auto name for sessions is not working, I still get the first message as a name."))
+      .toBe("Seems like auto name for sessions");
+  });
+
+  it("ignores skill blocks in fallback names", () => {
+    expect(fallbackSessionName('<skill name="x" location="/x">\nDo x\n</skill>\n\nCheck the UI now'))
+      .toBe("Check the UI now");
+  });
+});

src/server/sessions/sessionNameGenerator.ts

@@ -4,6 +4,7 @@ import type { ModelRegistry } from "@earendil-works/pi-coding-agent";
 const SESSION_NAME_TIMEOUT_MS = 10_000;
 const SESSION_NAME_MAX_INPUT_CHARS = 4_000;
 const SESSION_NAME_MAX_LENGTH = 60;
+const FALLBACK_SESSION_NAME_MAX_WORDS = 6;
 
 export async function generateShortSessionName<TApi extends Api>(modelRegistry: ModelRegistry, model: Model<TApi>, firstMessage: string): Promise<string | undefined> {
   const provider = getApiProvider(model.api);
@@ -23,7 +24,6 @@ export async function generateShortSessionName<TApi extends Api>(modelRegistry:
       }],
     },
     {
-      temperature: 0.2,
       maxTokens: 24,
       reasoning: "minimal",
       signal: AbortSignal.timeout(SESSION_NAME_TIMEOUT_MS),
@@ -43,10 +43,21 @@ export async function generateShortSessionName<TApi extends Api>(modelRegistry:
   return cleanSessionName(finalMessage === undefined ? streamedText : textFromAssistant(finalMessage));
 }
 
+export function fallbackSessionName(firstMessage: string): string | undefined {
+  return cleanSessionName(firstMessage
+    .replace(/<skill name="[^"]+" location="[^"]+">[\s\S]*?<\/skill>/g, "")
+    .replace(/```[\s\S]*?```/g, " ")
+    .replace(/[`*_#[\](){}<>]/g, " ")
+    .split(/\s+/)
+    .filter(Boolean)
+    .slice(0, FALLBACK_SESSION_NAME_MAX_WORDS)
+    .join(" "));
+}
+
 export function cleanSessionName(value: string): string | undefined {
   const title = (value.split("\n", 1)[0] ?? "")
+    .replace(/^\s*(title|session title)\s*:\s*/i, "")
     .replace(/^\s*["'`]+|["'`.]+\s*$/g, "")
-    .replace(/^(title|session title)\s*:\s*/i, "")
     .replace(/\s+/g, " ")
     .trim()
     .slice(0, SESSION_NAME_MAX_LENGTH)